Neutrophil Burst Oxidase Assay (CGD screening)

The Neutrophil Burst Oxidase Assay (CGD Screening) is a specialized flow cytometry-based test used to evaluate the ability of neutrophils to produce reactive oxygen species during the immune response. This process, known as the oxidative burst, is essential for destroying bacteria and fungi that invade the body.

The test is primarily used to screen for Chronic Granulomatous Disease (CGD), a rare inherited primary immunodeficiency disorder caused by defects in the NADPH oxidase enzyme complex. Individuals with CGD have impaired neutrophil function, making them more susceptible to recurrent bacterial and fungal infections, granuloma formation, and inflammatory complications.

The assay commonly uses Dihydrorhodamine 123 (DHR) and flow cytometry technology to measure neutrophil oxidative burst activity. Following stimulation, normal neutrophils generate reactive oxygen species that convert DHR into a fluorescent compound. Reduced or absent fluorescence may indicate impaired oxidative burst activity and suggest CGD.

This test is considered one of the most sensitive and reliable methods for diagnosing CGD and identifying carrier states in family members.

Benefits of the Test

• Screens for Chronic Granulomatous Disease (CGD)
• Evaluates neutrophil oxidative burst function
• Detects inherited phagocytic defects
• Assists in diagnosing primary immunodeficiency disorders
• Helps identify CGD carriers
• Supports early diagnosis and management

Why Doctors Recommend This Test

Doctors may recommend the Neutrophil Burst Oxidase Assay for:

• Recurrent severe bacterial infections
• Recurrent fungal infections
• Suspected Chronic Granulomatous Disease
• Family history of CGD
• Unexplained immune deficiency
• Recurrent abscess formation
• Persistent inflammatory conditions
• Carrier screening in affected families

The test helps determine whether neutrophils can effectively destroy infectious organisms.

Preparation Before Test

The test requires:

• Peripheral venous blood sample

Preparation generally includes:

• No fasting is required
• Inform your physician about current medications and recent infections
• Follow laboratory instructions for sample collection
• Fresh blood samples are often preferred for accurate analysis

Normal Reporting Time

Results are generally available within 2 to 5 working days, depending on laboratory workflow and testing methodology.

Who Should Take This Test?

• Children with recurrent severe infections
• Individuals with suspected primary immunodeficiency
• Patients with recurrent fungal infections
• Individuals with a family history of CGD
• Family members undergoing carrier screening
• Patients referred by immunologists, pediatricians, or hematologists

The assay is a key diagnostic test for evaluating neutrophil function and inherited immune disorders.

Clinical Significance

Abnormal results may be associated with:

• Chronic Granulomatous Disease (CGD)
• X-linked CGD
• Autosomal Recessive CGD
• Defects in NADPH Oxidase Complex
• Primary Phagocytic Disorders
• Inherited Immune Deficiencies

Reduced or absent oxidative burst activity suggests impaired neutrophil function and increased susceptibility to serious infections.

Important Note

Abnormal results require interpretation alongside clinical history, infection patterns, family history, and, when necessary, confirmatory genetic testing. Genetic analysis may be recommended to identify the specific mutation responsible for CGD.